The present invention concerns a device for the transfer of a mechanical force to a piezo-electric element for the generation of an electrical signal corresponding to the mechanical force, e.g. the tension of a thread or the like and/or the movement of the same, wherein the piezo-electric element is positioned in a holder in order to be actuated by the mechanical force on the end surfaces.

Disclosed herein is a method and associated adjusting system for adjusting the sensor sensitivity of a motion sensor for detecting movement of a pile yarn in a tufting machine, provided with several tufting needles, where this pile yarn is incorporated into a fabric. The method includes determining current process data, providing reference data for the sensor sensitivity of the motion sensor, including one or more sets, where each includes a value of a reference sensor sensitivity and corresponding process data, determining a connection between the current process data and the process data of the provided reference data, determining a value for the sensor sensitivity to be adjusted on the basis of this connection and the one or more values of the reference sensor sensitivity of the provided reference data, and adjusting the value for the sensor sensitivity to be adjusted in the motion sensor.